JP2019503732A - Apparatus and method for acquisition of medical images for ulcer analysis - Google Patents

Abstract

  An apparatus for capturing a medical image of an ulcer (1), arranged on the outer periphery of a closed regular planar geometry, each covering an ulcer (100) covering the surface of a wound (100) A light beam (104) captures a medical image of a plurality of light sources (2) adapted to irradiate in an overlapping manner and an ulcer (100) irradiated and irradiated within the periphery of the light source (2) Image capturing means (4) adapted to do so.

Description

  The present invention relates to capturing a medical image of an ulcer.

  More particularly, the present invention relates to an apparatus for capturing and processing a medical image of an ulcer, and a method for capturing a medical image of an ulcer.

  The term “skin ulcer” refers to a lesion that manifests itself in local parts of the body and in underlying tissues, due to a lack or lack of blood supply at that part. Unlike common wounds, ulcers have a limited or slow ability to recover due to insufficient blood volume supplied at the site involved.

  Ulcers are some irritating, such as diabetes, continuous and prolonged pressure on specific body parts (decubitus ulcers), or lesions or dysfunctions in vascular areas (venous or arterial ulcers) Or it can be caused by pathological factors.

  In addition to the above, depending on the level of national development considered and the state of the local medical system and structure, a proportion ranging from 1.2% to 18% of the total population suffers or is affected by skin ulcers, Sociological and statistical analysis shows.

  As an example, the US medical system alone has an annual cost of $ 35 to $ 7 billion for skin ulcer treatment.

  Currently, skin ulcers are treated through continuous and periodic specialist medications. During the examination, the doctor removes the previous bandage, visually determines the wound, and renews the bandage according to the situation. To determine the wound, it is necessary to consider three important parameters and their changes over time (relative to the previous visit).

  The main characteristics implying the recovery or worsening of the lesions are the following, wound spread, depth and color. By associating the three variables and comparing them to the previous state, the expert can apply the best medication and the ulcer is necrotic (mostly surgical resection of the tissue part, or worst case, the entire limb That require surgical resection), and in some cases, comprehensive drug treatment can be prescribed.

  Despite its proven therapeutic effects, this series of steps is forced to move to the place of treatment, regardless of the pain suffered and the various problems normally encountered in such situations Causes many inconveniences to the patient.

  It has been statistically proven that over 60% of people affected by this type of disease are over 65 years old and 90% of these people have severe walking problems. In some cases, some movements are potentially useless since the doctor is still unable to apply new types of medications after determining the condition of the ulcer.

  In general, however, most common medications can be applied by those who take care of the patient on a daily basis at home after being properly instructed by a specialist.

  Thus, unless strictly necessary, a need was felt to avoid unnecessary and detrimental patient outings to ulcer treatment sites. In addition, if the number of patients and the number of visits required for each patient (usually at least once every 2-3 months) are determined, it is difficult for the specialist to make a proper visit in a short time. .

In order to solve the above problem, the following devices have been created.
-Mavis (TM) is a stereolithography device that calculates its color and three-dimensional geometry by projecting parallel luminous strips at the site of the wound. Mavis is a large, non-movable device that cannot automatically detect and recognize wounds, and in fact, ulcers must be manually highlighted on the image by a doctor.
-Digikin ™ is a device that needs to use a digital camera and an optical raster to highlight the granulation pattern (changes in the pathology of the wound). Scars can be detected manually after the fact.
ATOS ™ and ATOSII ™ are stereo imaging methods for the analysis of skin ulcers that utilize two cameras to reconstruct a three-dimensional image of the wound. The image thus acquired is then analyzed by manually selecting the location of the lesion after the fact.
-Aranza Silhouette (TM) is a device that uses a laser scanner to capture an image of a wound. The lesion can then be detected and its diagnostic parameters can be calculated after subsequent manual detection.

  All of the above devices are not automatically wound detected in that they can only be used by a physician.

  In addition, the publication, De Francissis, S. , Et al. As described in "A new photocomputed measurement system for chronic wound assessment", Acta Phlbol 15 (2014), 13-8, the method described above illuminates the flaws during data capture. Be bothered by.

  Accordingly, the object of the present invention proposes an apparatus and method for capturing a medical image of an ulcer that can automatically and accurately detect a patient's ulcer and determine its morphological characteristics. That is. On the other hand, it also reduces the number of times the patient needs to go to the treatment site, which is only necessary if the doctor has to treat the ulcer directly.

  Some embodiments of the invention relate to an apparatus and method for capturing and processing a medical image of an ulcer that overcomes the shortcomings of the prior art.

  In one embodiment of the invention, an apparatus for capturing a medical image of an ulcer is arranged on the outer periphery of a closed, regular planar geometry, between the skin profile and the inside of the ulcer. A plurality of light sources adapted to irradiate the ulcer by covering the surface of the wound in a manner in which the respective light beams overlap in order to outline the shadow produced by the existing height differences, Image capturing means disposed within the perimeter and adapted to capture a medical image of the illuminated ulcer and detect both the illuminated and shadowed portions.

  In another embodiment, the apparatus further comprises a processing unit connected to the light source and the image capture means and adapted to control both ulcer illumination and image capture.

  In another embodiment of the present invention, the device further comprises a distance sensing device adapted to measure the distance between the device and the ulcer and to send an alarm signal if the distance exceeds a predefined threshold. Prepare.

  In another embodiment of the invention, the distance sensing device is either analog or digital, audio or optical. In another embodiment of the invention, there are at least three light sources. In another embodiment of the invention, the light source is a white LED.

  In another embodiment of the invention, the apparatus further comprises removable memory means adapted to store images captured by the image capture means. In another embodiment of the invention, the planar geometry has a minor axis of at least 10 cm.

  In another embodiment of the invention, the apparatus further comprises a data transmission device adapted to transmit data created by the processing unit to the remote device.

In another embodiment of the invention, a method for capturing and processing a medical image of an ulcer comprises
-Providing a device according to any one of the provisions listed above;
Positioning the device at a predefined distance from an ulcer directed towards the latter of the light source and the image capturing means;
-Sequentially capturing a plurality of images equal to the number of light sources plus one;
Performing the steps of combining and averaging the images, resulting in an output image;
Applying a “cellular automaton” algorithm to the output image, so as to obtain the contour of the ulcer and the contour of the shadow around the ulcer, each shadow over the edge of the respective contour Having respective portions of the ulcer extending longitudinally for each light source considered, and
Calculating the depth of the ulcer based on the length of the shadow portion defined from the contour of the shadow portion and the contour of the ulcer, as described above.

を実行する段階とを備え、ここで、Ｄはデカルト基準系におけるそれぞれの位置（ｘ_１，ｘ_２，ｘ_３）を有する光源のうちの１つにより放射される垂直光ビームと、考慮される影部分の輪郭との間の距離であり、γは、点Ｏを通過する光ビームにより限定される半角であり、最後にｐは、潰瘍の深さである。 In another embodiment of the invention, calculating the ulcer depth comprises:
- For Kakukage portion, comprising the steps of considering end-point F which belongs to the origin O, and ulcers contours belonging to the contour of the shadow portion, the point O and F, each of the coordinates in a Cartesian reference system (o _1, o ₂ F ₁ , f ₂ );
-For each shadow part, to calculate the depth of the ulcer corresponding to each shadow part,

Where D is considered a vertical light beam emitted by one of the light sources having a respective position (x ₁ , x ₂ , x ₃ ) in the Cartesian frame of reference. The distance between the shadow and the outline of the shadow portion, γ is a half angle limited by the light beam passing through the point O, and finally p is the depth of the ulcer.

に従って、画像捕捉手段と関連付けられるフォトセンサの、および画像捕捉手段の焦点開口角度のグリッドの次元の関数として計算する段階をさらに備え、ここで、ＡおよびＢは、フォトセンサのグリッドの矩形の側部の次元であり、Ａ_ｐｘは、出力画像の単一の画素の面積であり、Ｎ_ｐｘは、潰瘍の輪郭に含まれる画素数である。 In another embodiment of the invention, the method determines the area of the ulcer as

According to claim 1, further comprising the step of calculating as a function of the dimension of the grid of the photosensor associated with the image capture means and the focal aperture angle of the image capture means, wherein A and B are the rectangular sides of the grid of photosensors A _px is the area of a single pixel in the output image, and N _px is the number of pixels contained in the ulcer outline.

In another embodiment of the present invention, capturing a plurality of images comprises
-Gradually and sequentially turning on the light sources, each image being captured in a manner that the respective light source can be switched on and captured in an image capture means when captured And synchronizing with
-At the end of the gradual sequence, capturing the last one image with all light sources switched on simultaneously.

  In another embodiment of the invention, the image is captured as a color image and the output image has three different tones.

Further features and advantages of the present invention will become apparent in view of the following detailed description, which is provided as a non-limiting example with reference to the accompanying drawings.
1 is a perspective front view of an apparatus for capturing medical images according to the present invention. FIG. Figure 2 shows a wound illuminated by a light beam exiting the device of Figure 1; FIG. 3 is a diagram of the steps of a method for capturing medical images according to the present invention. FIG. 3 shows the wound of FIG. 2 with the wound outline and shadow highlighted. FIG. 2 is a cross-sectional view of the device of FIG. 1 positioned above the wound.

  Briefly, the present invention enables image capture of a patient's skin lesion via a video camera or photo camera comprising at least three light emitting devices (on a remote control device such as a smartphone, tablet, PC, etc.). It relates to a method for detecting and analyzing an image of a skin ulcer with a device that can be connected). Alternatively, the device may be stand alone.

  Data obtained after the subsequent stage of analyzing such an image can be transmitted to a doctor who then defines the patient's course of treatment (teletherapy, telediagnosis).

  The method for automatic detection of ulcers is based on image capture and image processing procedures. The method includes a crown of light sources, video cameras or photo cameras, and their cameras with known properties (emitted light intensity, color, and heat, and the angle of light emitted and incident on the wound) Requires the use of a control unit (whether embedded or external) to synchronize all such elements. The data thus obtained is then analyzed by a “cellular automaton” algorithm known per se to those skilled in the art.

  The “cellular automaton” (CA) algorithm is a specific kind of algorithm (Wolfram, Stephen. Theory and) based on the evolution of the internal state of a set of elements (called cells) arranged on a structured grid with finite dimensions. applications of cellular automata.Vol.1.Singapore: World Scientific, 1986).

  The cells of the grid evolve at precise time intervals and change their internal state according to external input and the state of neighboring cells.

  This class of algorithms is inspired by many types of evolutionary phenomena that can be identified in nature. Assuming that the cells of interest are associated with the pixels that make up the digital image, an algorithm (Itoh, Makoto, and Leon O. Chua. “Memristor cellular automata and memristor) can be designed, or can perform general image processing operations discrete-time cellular neural networks “International Journal of Bifurcation and Chaos 19.11 (2009): 3605-3656), or an algorithm that can recognize images (Secco, Jakopo, et al. nspired Algorithm ", IEEE ISOCC, Gyouju, South Korea (2015)).

  Documents CN 1971619 and TW2012031017 show how the CA algorithm is used for biomedical image analysis (especially magnetic resonance imaging (MRI)).

  FIG. 1 shows a perspective front view of an apparatus 1 for capturing medical images according to the present invention.

  The device 1 is captured by a crown of a light source 2, preferably a white LED, a video camera or photo camera 4, preferably of the CMOS type, located in the center of the crown of the light source 2, and a video camera or photo camera 4. Removable memory means 6 (not shown) adapted to store images, a distance sensing device 8 and a processing unit 10 are provided. The distance sensing device 8 may be either analog or digital, audio or optical.

  The light sources 2 are at least three and are arranged at regular intervals on the outer periphery of a regular planar geometry (circular crown) having a diameter of at least 10 cm.

  Alternatively, the light source 2 is arranged on any closed regular planar geometry with a minor axis length of at least 10 cm.

  The number of crown light sources 2 must be at least three in that it is the minimum number required to completely illuminate the wound with overlapping beams.

  FIG. 2 shows a wound (ulcer) 100 on the skin portion 102 illuminated by the light beam 104 emanating from the light source 2. Advantageously, the light beam 104 must cover the surface of the wound 100 in an overlapping manner, i.e., the sum of the N portions of the circumference acquired with the illuminating light beam 104 (the N-th fraction). , It must be larger than the area of the wound 100.

  The light source 2 has a known light intensity, color, and heat and emits a light beam or light beam at a predefined angle with respect to the surface of the wound 100.

  If the light source 2 is less, it must be too close to each other to provide a shadow of the respective differences in tissue height, which does not allow the entire surface of the pathological tissue to be covered I will. Since the average length of the skin ulcer major axis is approximately 7 cm, the diameter of the crown, preferably 10 cm, makes it possible to analyze all possible wounds.

  The processing unit 10 is connected to all of the components described above and is adapted to control the operation in a manner known per se. This implements the method described below. The processing unit 10 may be either a processor embedded in the device 1 or an external unit associated with a remote device 12 such as, for example, a smartphone, tablet, PC or the like. The processing unit 10 makes it possible to synchronize the operation of other components via its own internal clock.

  In a preferred variant of the invention, the device 1 is a data transmission device 14 (GSM®, 3G, which transmits a data packet representing an image to a remote device 12 or another device (not shown) available to the doctor. WiFi (registered trademark), 4G, and the like. Alternatively, device 1 and remote device 12 are connected via a USB cable.

  FIG. 3 shows a diagram of the steps of the method for analysis of medical images of ulcers according to the present invention.

  In particular, the method is to capture multiple images of the wound 100 with a video camera or photo camera 4, where the images are captured with controlled, variable brightness, and “cellular” Based on the subsequent processing of the image by the processing unit 10 through the “automaton” algorithm.

  The method for the analysis of medical images according to the invention consists in step 50 of a predetermined distance h from the wound 100 directed towards the latter of the crown of the light source 2 and the video camera or photo camera 4 in step 50. For example, in the range of 5 cm to 10 cm, the apparatus 1 is started by being positioned by the user.

  The distance sensing device 8 measures the distance h in a manner known per se. If the measured distance h exceeds a predetermined threshold, the distance sensing device 8 then emits an audible signal to alert the patient that the device 1 is not properly positioned. Alternatively, the distance sensing device 8 may emit a light emission signal or vibration.

  Alternatively, the distance h is measured manually by the patient or by reading the focus of the video camera or photo camera 4 and the focus of the connected optical element (in a manner known per se to the person skilled in the art).

  During the next step 52, the user starts the image capture phase by pointing the video camera or photo camera 4 towards the wound 100 and pressing a start button on the video camera or photo camera 4, for example. In particular, N + 1 images of the wound 100 are captured, where N is the number of crown light sources 2.

  The crown light sources 2 are turned on one by one in turn and synchronized with the image capture made by the video camera or photo camera 4. Thereby, each light source 2 is switched on, and one image is captured. When a new light source 2 is turned on, the previously lit one is turned off, so that the wound is illuminated by one light source 2 at a time. At the end of the sequence, the video camera or photo camera 4 captures the last one image with all light sources 2 switched on at the same time.

  The circular crown arrangement of the light source 2 makes it possible to illuminate the wound from different angles and to create a shadow on the wound itself, thereby highlighting any uneven part of the scratched surface. Furthermore, the crown formed by the light source 2 having a predefined characteristic ensures that the lesion 100 is precisely illuminated, thus preventing variation in results over the long term.

  FIG. 4 shows the wound 100 of FIG. 2 highlighting the outer periphery or contour 101a of the wound 100 and a series of shadow portions 101 that generally have the outer periphery or contour 100a.

と等しい因数により画像を結合するおよび平均化することによって低減でき、ここで、Ｋは捕捉画像の数である。これは、装置１を支えている手の筋肉の震えにより引き起こされるモーションアーチファクトを大幅に低減する。画像は、カラー画像、すなわちＲＧＢコード画像として捕捉される。 By increasing the number of images of ulcer 100 captured from the same location, the signal to noise ratio is

Can be reduced by combining and averaging the images by a factor equal to, where K is the number of captured images. This greatly reduces motion artifacts caused by trembling of the hand muscles supporting the device 1. The image is captured as a color image, ie an RGB code image.

  In a subsequent step 54, operations to combine and average the RGB images are performed, resulting in an output image of the wound 100 having three different tones.

  At this point, the image processing stage 56 is performed using a “cellular automaton” algorithm known to those skilled in the art that is applied to the output image. The algorithm executed by the processing unit 10 can recognize the contours 101a and 100a of the scratch 100 and the contours 101a and 100a of the shadow portion 101, respectively, and can automatically segment and decode the colors.

  The color of the damaged area is decoded by generating a color map and utilizing the output image values obtained in step 54.

  The number of photosensors in the video camera or photo camera 4 is equivalent to the number of pixels in the captured image (hereinafter referred to as px). The grid of CMOS video camera or photo camera photosensors preferably has a rectangular shape and thus has a long side A and a short side B (see FIG. 5), but different shapes, for example circular or square Can also be included.

FIG. 5 is a cross-sectional view of the device 1 positioned above the wound 100. The cross-sectional view comprises a video camera or photo camera 4 and a crown having a respective position X (x ₁ , x ₂ , x ₃ ) and position Y (y ₁ , y ₂ , y ₃ ) in a Cartesian frame of reference. A single light source 2 is shown.

  The video camera or photo camera 4 has a previously known focal aperture λ and is associated with a rectangular grid of photosensors 200 each having a long side A and a short side B in a manner known per se. The light source 2 is disposed at a distance h from the skin 102 with the wound 100 and emits a light beam 104 having a radiation half angle φ / 2 directed towards the wound 100.

  References 100 a ′ and 101 a ′ indicate two points, the outline 101 a of the scratch 100 and the outline 100 a of the shadow portion 101, respectively. The reference γ indicates a half angle limited by the light beam 104 passing through the point 100a ′ of the outline 101a of the wound 100. The reference D indicates the distance between the vertical ray emitted by the light source 2 and the outer periphery 101a of the ulcer 100, whereas L is the point 100a ′ of the contour 101a and 100a of the wound 100 and of the shadow portion 101. And the distance projected on the plane of the flaw between the point 101a ′.

  For the data obtained in step 56 by the “cellular automaton” algorithm, during step 58, processing unit 10 calculates the area of lesion 100 using the following equation, where subscripts A and B are photo Refers to the relevant side of the sensor grid.

によりもたらされる。単一の画素（Ａ_ｐｘ）の面積は、

によりもたらされる。 The focal area (A) of the video camera or photo camera 4 is

Brought about by. The area of a single pixel (A _px ) is

Brought about by.

によれば、境界１０１ａに含まれる画素数Ｎ_ｐｘにＡ_ｐｘを乗じると、結果として病変１００の面積をもたらす。 Next formula

According to the above, multiplying the number of pixels N _px included in the boundary 101 a by A _px results in the area of the lesion 100.

  Subsequently, in step 60, for each shadow portion 101, the processing unit 10 calculates a shadow length L starting from its origin to determine the depth p of the scratch 100.

が、傷１００の深さｐを計算すべく実行される。 For a given shadow portion 101 generated by a single light source 2, for example, the origin O (o ₁ , o ₂ ) corresponding to the point 100a ′ and the end point F (f ₁ , f ₂ ) corresponding to the point 101a ′. (O and F are therefore known only in the two-dimensional plane when the image is captured, the distance representing the length L of the shadow portion). During this phase 60, therefore the following operations

Is performed to calculate the depth p of the flaw 100.

  Step 60 is repeated for each image in the contour 101a, resulting in a plurality of depth values p representing the depth of the wound 100 along the entire outer periphery 101a.

  Finally, during step 62, final data (particularly its depth and area) regarding the wound 100 is output to the processing unit 10.

  Advantageously, the final data is either stored in the memory means 10 of the device 1 or transmitted to the doctor through the data transmission device 14.

Therefore, the device 1 of the present invention has the following innovative features.
-Has complete control over the brightness of the image, often resulting in less external light emission noise that creates artifacts in the processed image.
-Contains a data transmission module so that it can be used for remote diagnosis.
-Multi-image packets are used to automatically detect wounds and calculate ulcer depth, each image having a known intensity and color but obtained with monochromatic light from a spatially variable light source . This allows the image processing algorithm to understand the three-dimensional nature of the wound through the change in shadow produced by the indentation at the ulcer boundary.
-This is the first telemedicine device for this purpose that should not be used exclusively by skilled or pre-trained personnel. The use of this device is left entirely to the patient, which improves portability. As explained above, this device also allows the physician to downstream the use of the device for accurate and effective remote diagnosis and follow-up of the patient's condition, while the need for the latter (Such as difficult walking, elderly, clinical condition to prevent movement).
-The device is cheap to develop and manufacture because it utilizes simple technology.

  Of course, without detracting from the principles of the invention, the details of the embodiments and implementations are hereby given as non-limiting examples without departing from the protection scope of the invention as set forth in the appended claims. What is described and shown in the specification may vary widely.

Claims (14)

A device for capturing a medical image of an ulcer,
A plurality of light sources arranged on the outer periphery of a closed regular planar geometry, irradiating the ulcer in an overlapping manner with respective light beams covering the surface of the ulcer;
An image capturing means disposed within the outer circumference of the plurality of light sources and capturing a medical image of the irradiated ulcer.   The apparatus of claim 1, further comprising a processing unit connected to the plurality of light sources and the image capture means to control both the irradiation of the ulcer and the capture of the medical image.   The device according to claim 1, further comprising a distance sensing device, measuring a distance between the device and the ulcer, and transmitting an alarm signal if the distance exceeds a predefined threshold.   4. The apparatus of claim 3, wherein the distance sensing device is either analog or digital, audio or optical.   The apparatus according to claim 1, wherein the plurality of light sources is at least three.   The apparatus according to claim 1, wherein the plurality of light sources are white LEDs.   The apparatus according to any one of claims 1 to 6, further comprising removable memory means for storing the medical image captured by the image capturing means.   8. A device according to any one of the preceding claims, wherein the closed regular planar geometry has a minor axis of at least 10 cm.   9. The device according to any one of claims 1 to 8, further comprising a data transmission device for transmitting data created by the processing unit to a remote device. A method for capturing and processing a medical image of an ulcer, comprising:
Providing a device according to any one of claims 1 to 9;
-Positioning said device at a predefined distance from said ulcer directed towards the latter of said plurality of light sources and image capture means;
Sequentially capturing a plurality of images equal to the number of light sources plus one;
Performing the steps of combining and averaging the plurality of images, thereby obtaining an output image;
Applying a “cellular automaton” algorithm to the output image, so that a contour is obtained for the ulcer contour and a shadow portion in the surface of the ulcer, each shadow portion having its own contour Having respective portions of the ulcer extending longitudinally for each light source considered beyond the edges of
Calculating the depth of the ulcer based on the length of the shadow portion defined starting from the contour of the ulcer and the contour of the shadow portion. The step of capturing a plurality of images comprises:
Progressively and sequentially turning on the plurality of light sources, wherein each image is captured in a manner such that each light source can be captured as the respective light source is switched on. Synchronizing with the acquisition of the plurality of images by:
The method of claim 10, comprising: at the end of the gradual sequence, capturing the last one image with all light sources switched on simultaneously. The step of calculating the depth of the ulcer comprises
-For each shadow part generated by each single light source, considering the origin O belonging to the contour of the ulcer and the end point F belonging to the contour of the shadow part, the origin O and the end point F has respective coordinates (o ₁ , o ₂ ; f ₁ , f ₂ ) in a Cartesian frame of reference, and the distance represents the length (L) of the shadow portion;
-For each image, to calculate the depth of the ulcer corresponding to each shadow part,

Where D is a vertical light beam emitted by one of the plurality of light sources having a respective position (x ₁ , x ₂ , x ₃ ) in the Cartesian frame of reference, and A distance between the contour of the shadow portion to be made, γ is a half angle limited by the vertical light beam passing through the origin O, and p is the depth of the ulcer. The method of claim 11, comprising: The area of the ulcer is given by

Is calculated as a function of the grid dimension of the photosensor associated with the image capture means and the focal aperture angle (λ) of the image capture means, wherein A and B are The dimensions of the rectangular sides of the grid, A _px is the area of a single pixel of the output image, and N _px is the number of pixels contained in the contour of the ulcer 13. A method according to claim 10 or 12, comprising.   The method of claim 13, wherein the plurality of images are captured as color images and the output image has three different tones.

Images